Xesús Prieto

Mode-division multiplexed transmission with inline few-mode fiber amplifier

We demonstrate mode-division multiplexed WDM transmission over 50-km of few-mode fiber using the fibers LP01 and two degenerate LP11 modes. A few-mode EDFA is used to boost the power of the output signal before a few-mode coherent receiver. A 6×6 time-domain MIMO equalizer is used to recover the transmitted data. We also experimentally characterize the 50-km few-mode fiber and the few-mode EDFA.

1.05Pb/s Transmission with 109b/s/Hz Spectral Efficiency using Hybrid Single- and Few-Mode Cores

We demonstrated 1.05-Pb/s transmission over 3km of multicore fiber with spectral efficiency of 109b/s/Hz, using twelve single-mode cores carrying DP-32QAM-OFDM signals and two few-mode cores carrying DP-QPSK in their LP01 and two LP11 modes.

SDM transmission of real-time 10GbE traffic using commercial SFP + transceivers over 0.5km elliptical-core few-mode fiber

We experimentally demonstrate the first few-mode space division multiplexed (SDM) transmission of real-time 10Gb/s Ethernet (10GbE) traffic using commercial small form-factor pluggable SFP + transceivers without coherent detection or multiple input multiple output digital signal processing (MIMO-DSP) over 0.5km elliptical-core few-mode-fiber, achieving <-26dB crosstalk between LP(11e) and LP(11o) modes at 1.3μm.

A novel refractive index profile for optical characterization of nonlinear diffusion processes and planar waveguides in glass

Abstract A novel refractive index profile, consistent with nonlinear diffusion processes in glass, is proposed for graded index (GRIN) planar waveguides. This new profile matches with great accuracy most of the waveguides fabricated by ion-exchange in glass, and it provides simple relationships between the real diffusion parameters and the effective ones obtained by fitting to the experimental results. In this way, physical parameters such as the diffusion coefficients can be easily determined and the numerical solution, describing the ion-exchange process, can be directly selected.

Increasing resistivity effects in field-assisted ion exchange for planar optical waveguide fabrication

An improved description of the usual field-assisted ion-exchange processes for fabricating planar surface optical waveguides in glass substrates is presented that takes into account both increased resistivity because of incoming ions and the substrates finite thickness. Time dependencies of the ion flux density, effective depth, and profile shape are predicted.

Three-step Diffused Surface Waveguides for Fabricating and Designing Integrated Optical Components

Abstract An experimental technique of a three-step silver-sodium ion exchange in soda-lime glass substrates is presented. Two ion exchanges in different regions on the substrate are realized, followed by a post-baking such that the waveguide parameters in each region can be predicted accurately. By a proper choice of the fabrication parameters a high transmission is obtained. Theoretical and experimental results on an integrated optical component (a set of 17 waveguide lenses) are presented.

6×28-Gbaud few-mode recirculating loop transmission with gain-equalized inline few-mode fiber amplifier

Using a transmission fiber with a zero differential modal dispersion wavelength and a gain-equalized few-mode EDFA, we demonstrate mode-multiplexed transmission over a fiber recirculating loop with all few-mode components.

Graded-index bifocal spectacle lenses produced by ion-exchange in glass: paraxial designing

We present the preliminary results about the paraxial design of graded-index (GRIN) bifocal spectacle lenses fabricated by a local ion-exchange technique in glass. Paraxial formulae for the optical power are calculated for two refractive index profiles modelling the GRIN region, Erfc and Gaussian, which correspond to a linear and nonlinear ion-exchange regime, respectively.

Prediction of space-charge density and space-charge field in thermally ion-exchanged planar surface waveguides

Using an accurate analytical expression for describing the numerical solution of the diffusion equation in planar ion-exchanged waveguides, we present normalized depth profiles for space-charge field and density as a function of the mismatch in the self diffusion coefficients of the two cations. Our results are presented in terms of analytical expressions as well as universal curves, useful for any cation pair, substrate glass, or salt. It is also shown that most of the analytical expressions for the refractive index profile used in the literature yield unphysical results.

Glass processing by ion exchange to fabricate integrated optical planar components: applications

Ion-Exchanged Glass Integrated Optics has received a considerably attention during the laser years because of their well-known advantages. On the other hand, ion- exchanged waveguide components are finding important applications in the implementation of analogue processing devices, optical sensing devices and some kind of circuit for optical communications. Many of these develop devices are based on channel guides, however planar components with optical confinement in only one dimension have been also recognized to be among the basic components of glass integrated optics. In this paper we show the specific advantages of using these kinds of integrated optical elements. Thus, conventional photolithographic techniques can be used with a great accuracy but within the high requirements needed for channeled devices. Likewise, as it will be shown, the components can be realized by simple selective ion-exchange processes in a few steps, and with a high transmission of guided light, in a monomode regime, through the various boundaries shaping the planar components. Finally, their planar configuration facilitates considerably the use of glass integrated devices with other materials and thus a high-performance hybrid optical devices can be achieved. In short, we show various approaches to the design and fabrication of planar components and presents several passive components implementing simple functions such as: beam-splitting, focusing, and so on, which are important for optical sensing and processing applications.